ArooBaito,

other people will probably also recommend this, but here is one more
vote for Tim's chapter of the Squeak book as a great starting point:

http://www.rowledge.org/resources/tim%27s-Home-page/Squeak/OE-Tour.pdf

Though Eliot's blog is about what he changed from that, the first part
of each entry is a really good explanation of "how things used to be"
(which is what you want to know about):

http://www.mirandabanda.org/cogblog/

(see the numbered entries on the left under "COG")

-- Jecel